1. Field of the Invention
The present invention relates to a vehicle control apparatus, and more particularly to a vehicle control apparatus for controlling the output reduction of a power source.
2. Related Art
In general, a vehicle has three basic and necessary abilities including an ability to advance as a driving force, an ability to turn as a steering force, and an ability to stop as a braking force.
The driving force is obtained as a reaction force to the frictional force between driving wheels and a road surface by generating a power, i.e., a torque, from a power source of an internal combustion engine (hereinafter simply referred to as an engine) in response to the depression amount of an accelerator pedal or the like and transmitting the generated torque through a transmission to the driving wheels to allow the driving wheels to travel thereon. The steering force is obtained by a steering device capable of changing the advancing direction of, for example, front wheels in response to the operation amount of a steering wheel. The braking force is obtained as a reaction force by generating a frictional force in the advancing direction between the driving wheels and the road surface by slowing down or stopping the rotation of the wheels in response to the depression amount of a brake pedal or the like to allow the vehicle to be stopped.
Generally, the accelerator pedal and the brake pedal are located adjacent to each other close to the location of driver's feet. Many drivers depress selectively the accelerator pedal or the brake pedal only with his/her right foot to control the driving force and the braking force, viz., to control a vehicle speed.
In this case, a vehicle with an automatic transmission (hereinafter simply referred to as an AT car) is provided with no clutch pedal. This causes some drivers to depress the brake pedal with his/her left foot so as to drive their cars using their left foot and right foot separately to depress the brake pedal and the accelerator pedal, respectively. For such drivers using both their feet separately for the brake pedal and the accelerator pedal, there may be a possible situation that the brake pedal is depressed while the accelerator pedal is not yet released by the driver or the accelerator pedal is depressed while the brake pedal is not yet released by the driver.
Therefore, the intention of the driver is not always to reduce the speed when the both accelerator and brake pedals are being depressed, and this may lead to the deterioration of drivability.
Apparently, there has so far been a vehicle control apparatus known to reduce an engine torque in the event that the accelerator pedal and the brake pedal are depressed at the same time (see, for example, Patent Document 1).
The previously mentioned conventional vehicle control apparatus is constructed to reduce the torque output from the engine by temporarily reducing the amount of fuel injection to the engine in the event that the accelerator pedal and the brake pedal are depressed at the same time.
In some modern vehicle control apparatuses, a vehicle behavior stabilization control that stabilizes the behavior of the vehicle is provided. Such vehicle behavior stabilization control includes a traction control system (TRC) and an anti-skid control device.
The TRC is to prevent slipping of the driving wheels at the time of starting or accelerating the vehicle. For example, the TRC is adapted to determine the slipping of the driving wheels from the vehicle speed, the rotation speed of each of the wheels, and the like, and then reduce or adjust the torque output from the engine to eliminate the slipping situation.
A typical anti-skid control device known includes a vehicle stability control (VSC). The VSC maintains the stability of a vehicle at the time of driving through a turn, avoiding an obstacle, or the like. More specifically, the VSC prevents skidding when the vehicle loses the balance due to entering a corner at an excessive speed or an operation of abrupt steering wheel, exercising an excellent driving stability. For example, the VSC detects the vehicle balance and the like with sensors and, if a situation of understeer is detected, the VSC reduces the torque output from the engine and applies braking to the rear wheel on the inner side of a turn. When a situation of oversteer is detected, the VSC applies braking to the front wheel on the outer side of the turn. The VSC controls the engine and the braking in response to the drive state to prevent skidding, wide turns, or the like of the vehicle, thereby allowing the vehicle to travel safely through a corner without needing a driver to consciously make adjustments in driving operation.